Generally, a tail gate is mounted at a rear portion of a sports utility vehicle, a recreational vehicle, a hatch-back type vehicle, a van, and the like so as to provide a wide and open loading space.
Recently, a tail gate capable to be automatically opened has been equipped in a vehicle so that when a user carrying a smart key approaches the tail gate up to a predetermined distance, the tail gate will be automatically opened.
Referring to FIG. 1, if the user uses the tail gate function, a process of sensing that the user carrying the smart key approaches the tail gate up to a predetermined distance to issue an alarm (sound+lamp), a process of performing an authentication procedure between the smart key and a smart key controller installed in the vehicle, and a process of issuing, by the smart key controller, an open instruction to the tail gate are performed, and thus the tail gate is automatically opened together with an open alarm (sound+lamp).
In this case, a sensing distance between the user carrying the smart key and the tail gate is fixed to about 1.0 m.
However, the existing tail gate system has the following problems.
First, when the user approaches the tail gate in a state in which he/she does not intend to open the tail gate, automatically opening the tail gate may occur while an alarm process of turning on an alarm sound and an alarm illumination is performed.
Second, since the sensing distance between the user carrying the smart key and the tail gate is fixed to about 1.0 m, when the user carries a load, the tail gate may collide with the load at when the tail gate is automatically opened.
Third, as illustrated in the accompanying FIG. 2, if a vehicle is parked in a garage, when the user carrying the smart key is located, having a garage door disposed therebetween, that is, when the user is located at a distance of about 1 m from the tail gate, having the garage door disposed therebetween, automatically opening the tail gate may occur while the alarm process of unexpectedly turning on the alarm sound and the alarm illumination is performed. Thus, the tail gate may be damaged due to a collision with the shutter while the tail gate is automatically opened.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.